<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            list-style: none;
            text-decoration: none;
        }

        .box {
            width: 1030px;
            margin: 50px auto;
        }

        .box ul {
            display: flex;
            justify-content: center;
        }

        .box ul li {
            margin: 0 5px;
        }

        .box ul a {
            display: inline-block;
            perspective: 300px;
        }

        .box ul span {
            display: inline-block;
            background-color: #369;
            color: white;
            line-height: 40px;
            width: 100px;
            text-align: center;
            position: relative;

            transition: all 0.5s;

            transform-style: preserve-3d;
        }

        .box ul span::after {
            content: attr(data-content);
            position: absolute;
            top:100%;
            left:0;
            background-color: #369;
            width: 100%;
            height: 100%;
            transform-origin: top;
            transform: rotateX(-90deg);
        }

        .box li a:hover span{
            transform-origin: top;
            transform: rotateX(90deg) translateY(-20px);
        }

    </style>
</head>
<body>
<div class="box">
    <ul>
        <li><a href="#"><span data-content="第一页">网站导航</span></a></li>
        <li><a href="#"><span data-content="第二页">网站导航</span></a></li>
        <li><a href="#"><span data-content="第三页">网站导航</span></a></li>
        <li><a href="#"><span data-content="第四页">网站导航</span></a></li>
        <li><a href="#"><span data-content="第五页">网站导航</span></a></li>
        <li><a href="#"><span data-content="第六页">网站导航</span></a></li>
    </ul>
</div>
</body>
</html>